2,336 research outputs found

    LASIG II - Pulsed laser ion generator study Final report

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    Ion current produced by illuminating materials with focused output of pulsed ruby lase

    The Behavior of Soluble Salt in Sharkey Clay

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    Soluble salt problems do exist and are significant in Arkansas. Studies have been conducted on Crowley silt loam (Typic Albaqualfs) which have established the behavior of soluble salt in that soil. The major objective of this study was to quantify the behavior of soluble salt in a second important Mississippi River Delta soil - the Sharkey (Vertic Haplaquepts). To this end, estimation of the downward redistribution of salt and the estimation of various components of the water balance for this soil served as specific objectives. Field studies were designed to monitor the movement of salt in the Sharkey soil and to characterize selected components of the water balance. In total, three tentative conclusions may be drawn from the data. First, the infiltration for the Sharkey soil was approximately three times that of the Crowley silt loam. The average value was 29 cm for the rice season. Second, levee seepage, while significant for small plots, was shown to be small for production-sized fields. Levee seepage remained relatively constant throughout the season and averaged 0.025 nvfym/d. And third, downward redistribution of salt was large and appeared to follow a pattern where a peak occurred at the surface and, possibly, at the lower soil depths

    Organ failure, outcomes and deprivation status among critically ill cirrhosis patients — a one-year cohort study

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    Satellite telemetry of Great Frigatebirds Fregata minor rearing chicks on Tern island, North Central Pacific Ocean

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    The Papahānaumokuākea Marine National Monument in the Northwestern Hawaiian Islands protects breeding habitat for many migratory animals. We used satellite telemetry to describe the areas in which a mobile top predator, the Great Frigatebird Fregata minor, traveled on foraging trips during the early chick-rearing period from a breeding colony on Tern Island, French Frigate Shoals. Identification of potential foraging events, indicated by a reduction in transit rate, allowed us to assess whether wide-ranging marine species such as Great Frigatebirds remain inside the protective boundaries of the Monument while brooding young chicks. Four of 11 foraging trips extended outside of the boundaries of the Monument. These movements may represent the shortest foraging distances that Great Frigatebirds travel from the colony because adults need to provision young chicks frequently. We also tracked one male that abandoned its nest on a journey to the southwest of Tern Island. This bird was tracked for 16 days before the transmitter\u27s battery expired, and the last transmitted position was nearly 1100 km from Tern Island. These tracks, the first reports of frigatebird telemetry in the Pacific Ocean, provide information about the foraging behaviors of a top predator during a critical life-history stage-data that will complement tracking data of other species and aid in future conservation and management decisions concerning the Monument and surrounding waters of the Northwestern Hawaiian Islands

    Multi-transmission-line-beam interactive system

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    We construct here a Lagrangian field formulation for a system consisting of an electron beam interacting with a slow-wave structure modeled by a possibly non-uniform multiple transmission line (MTL). In the case of a single line we recover the linear model of a traveling wave tube (TWT) due to J.R. Pierce. Since a properly chosen MTL can approximate a real waveguide structure with any desired accuracy, the proposed model can be used in particular for design optimization. Furthermore, the Lagrangian formulation provides for: (i) a clear identification of the mathematical source of amplification, (ii) exact expressions for the conserved energy and its flux distributions obtained from the Noether theorem. In the case of uniform MTLs we carry out an exhaustive analysis of eigenmodes and find sharp conditions on the parameters of the system to provide for amplifying regimes

    Canine distemper virus neutralization activity is low in human serum and it is sensitive to an amino acid substitution in the hemagglutinin protein

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    © 2015 Elsevier Inc.Serum was analyzed from 146 healthy adult volunteers in eastern Africa to evaluate measles virus (MV) and canine distemper virus (CDV) neutralizing antibody (nAb) prevalence and potency. MV plaque reduction neutralization test (PRNT) results indicated that all sera were positive for MV nAbs. Furthermore, the 50% neutralizing dose (ND50) for the majority of sera corresponded to antibody titers induced by MV vaccination. CDV nAbs titers were low and generally were detected in sera with high MV nAb titers. A mutant CDV was generated that was less sensitive to neutralization by human serum. The mutant virus genome had 10 nucleotide substitutions, which coded for single amino acid substitutions in the fusion (F) and hemagglutinin (H) glycoproteins and two substitutions in the large polymerase (L) protein. The H substitution occurred in a conserved region involved in receptor interactions among morbilliviruses, implying that this region is a target for cross-reactive neutralizing antibodies

    The Behavior of Soluble Salt in Sharkey Clay- II

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    Soluble salts have been shown to accumulate in Arkansas soils in sufficient quantities to impair crop plant growth. The major objective of this study was to describe the behavior of soluble chloride salt over long time periods in Sharkey clay - a major Mississippi Delta soil. Prior to flooding rice, leaching of chloride in response to rainfall was observed. The inclusion of a sandy subsoil layer reduced this effect presumably by limiting downward movement of water under unsaturated conditions. No lateral movement of the chloride salt was found during the period prior to flooding. Removal of soluble chloride salts from the top 100 cm of Sharkey soil was complete in a 1-2 year period depending on weather conditions. In a year where the rice cropping season was followed by a wet winter, losses were smaller than in a year where the rice cropping season was followed by a drier winter. These results suggested that removal of soluble salts via leaching in this soil was more efficient under less saturated soil conditions
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